dearborn



Sept. 11,- i C. ALDEARBORN :BLINDSTITCH SEWING MACHINE Filed May 17 1921 Patented Sept. l1, 1923.

y 1,467,570 PATENT OFFICE.

CHARLES DEARBORN, OF NEW YORK, N. Y.

BLrNDsrrrcrr snwrne lfini-icnina.

Application led May 17,

To all whom it may concern:

Be it known that I, CHARLES A. DEAR- BORN, a citizen of the United States, residing in the borough of Manhattan, city, county, and State of New York, have invented cer-' tain new and useful Improvements in Blindstitch Sewing Machines, of which the following is a specification.

rThe present invention relates to improvements in stitch forming mechanism for blind stitch sewing machines of the type covered by Patents No. 705,325 granted toy me July 22, 1902, and No. 814,026 granted to me March 6, 1906.

Blind stitch sewing machines of the type referred to have been in commercial use for a number of years, particularly for` manufacturing clothing. These machines are operated at very high rates of speed and are required to be extremely accurate in all details. of this type of machine, the present invention improves the structure of the looper and its mounting to cause it to cooperate more efficiently with the reciprocating upper feed mechanism of the machine.

In accomplishing the desired object, they looper rod is formed at its forward end with an angular head offset slightly from the looper rod and shaped to accurately receivel the channelled heel of the looper proper which is formed of a sheet steel stamping, longitudinally channelled for strength and stiffness and having a slot for passage of a set screw which is threaded into the offset head of the looper rod.

The looper rod is provided, back of the offset head referred to, with a spherical bearing that is engaged by a spherical bearing yoke formed upon the depending rock arm extending from .an elongated bearing sleeve that is journalled upon an adjustable block carried in the sewing'machine arm.

This suspended bearing yoke is formed of two plates separated in a plane transverse to the axis of the looper yrod and formed with complementary spherical recesses on their inner faces to engage the ball ofthe rod and with openings in their faces for the looper rod to project through. To permit the bearing yoke to operate ina vertical, longitudinal plane as close as possible to the plane 0f operation of the reciprocating upper feed bar, the inner edges of the plates forming the yoke are cut away in a vertical plane so that the rocking bearing 'Io further insure the accuracy isf-31,y j semi No. 470,285.

yoke will operate in close proximity to theretaining disk fastened alongside of the bearing of the reciprocating feed bar. By this arrangement, the effective long bearing for the rocking yoke is provided, while at the same time the parts are brought into close proximity so as to enable them to 'effectively cooperate with the least complications` of movements.

In order that the invention may be fullyr `part of the looper rod and removable looper.

The type of machine to which the present improvements apply is well known in the art and is illustrated in the patents above referredto.` The drawing shows onlysufcient'of the4 machine to connect up the stitch yforming mechanism to which the present improvements relate.

5 represents the forwardly projecting arm of the'lsewing machine frame and 15 the main driving shaftgfrom which the operative parts receive motion. 'Ihe shaft 15 carries the feed actuating eccentric'l?, the needle actuating` eccentric 53 and the looper actuat- 7 ing crank disk 18. A cylindrical block 32 is adjustably mounted in the sewing machine army 5 and held in the desired. adjusted position by means of the set screw 35. rIhis block 32 carries an eccentric bearing pin 31 which projects laterally and horizontally from the arm 5 and has journalled upon it a sleeve 30 formed integral with the main portion of the downwardly projecting sectional'bearing yoke presently to be described.

The bearing yoke referred to comprises a plate 50 formed integral with the sleeve 3G` and a complementary removable plate 51` secured to the face of the plate 50 by means' of set screws 55. Plates 50, 51 are formed with axial openings that are encal plane as indicated at 62 in Figure 3 of 4 the drawing for the purpose of affording room between the rocking yoke of the looper and the bearing of the upper feed member hereinafter described.

The crank disk 18 carries a. crank arm 19 projecting from it at an angle of approximately 45 degrees and rigidly mounted upon the crank arm 19 is a crank pin 2O which is presented at an angle of about 45 degrees to the shaft 15. Freely swivelled upon the crank pin 2O is a sleeve 21 having pivoted to it at 21a a yoke 2Q, to which is adjustably secured the rear end of the looper rod 25. The looper rod is formed adjacent to its forward end with a spherical bearing 38 which is freely journalled in the rocking yoke 50, 51 above referred to. The bearing between the ball 3S and the rocking yoke provides a form of universal joint, permitting the looper rod to move forwardly and backwardly with the rocking yoke while the looper rod rocks in the bearing yoke laterally and up and down in carrying out its stitch forming functions.

The extreme forward end of the looper rod is provided with an angular offset shoulder 70 which is shaped to receive the channelled heel of the looper proper 75. The looper proper is preferably formed of a sheet steel stamping, it being given the. channelled formation for strength and rigidity and the looper fingers being properly shaped at the forward end of the curved looper arm. ln the heel portion of the looper 75 is formed a slot 7G, through which passes the set screw 77 threaded into a suitable opening in the angular head. of the looper. rod.

\ To properly illustrate the advantages of the improved looper mechanism, I have illustrated in the drawing the upper reciprocating feed device with which the improved looper cooperates. This feed device is substantially the same in general principle as the feed mechanism covered by my above named Patent No. 814,026 and comprises essentially a. feed dog 130 projecting laterally from the forward end of a longitudinally movable rocking arm or. bar 138. This arm or bar 133 is formed between its ends with an elongated slot 134 in which engages an anti-friction roller 135 mounted upon a pin or screw 133. Disks or washers 139 and 140 are also confined upon the screw 138 upon opposite sides of the feed bar 133 for confining and guiding it in its rocking reciprocations. The rear end of 'the feed bar. 133 is formed with a yoke 136` which embraces the eccentric 137 upon the main driving shaft 15 above referred to.

Referring now particularly to Figure 3 of the drawing, it will be observed that the cutaway portion 62 of the rocking bearing yoke of the looper permits the mounting of the looper in a plane close to and approximately parallel with the plane of operation of the feed bar 133. This close parallel relationship is very important from the standpoint of efficiency in a rapidly operating sewing machine. This mounting of the looper affords a desirable long bearing for the rocker without interfering with the effectiveness of the universal joint upon which the looper is mounted.

l claim 1. In a sewing machine, thecombinationl .of a machine frame, a bearing pm projecting laterally from said frame, a rocker arm having an elongated bearing j ournalled upon said pin and a yoke depending from said bearing, a looper having a universal joint bearing in said depending yoke, and a feed bar mounted upon the machine frame between the frame and said depending yoke, said yoke being cut away on its inner edge to permit the close association of the looper and feed bar substantially set forth.

2. In a sewing machine, the combination of a machine frame, a reciprocating feed bar mounted approximately in a horizontal plane upon said frame, a rocker arm journalled upon said frame directly above said feed bar to rock forward and backward in a vertical plane approximately parallel with and alongside of said feed bar, said rocker arm comprising a depending yoke formed with a spheroidal bearing socket and an inner cutaway face to permit the close association of said rocker arm and feed bar in said parallel planes, a looper rod having universal joint driving mechanism connected with its rear end, a looper upon the forward end of said looper rod, and a spherical bearing between the ends of said looper rod which engages said bearing yoke of the rocker arm.

3. In a sewing machine, the combination of a machine frame, suitable feed mechanism, a looper comprising a looper. rod mounted for loop forming motions and having at its forward end an offset, angular shoulder and a looper proper of substantially U-shape cross section formed of a sheet metal stamping and having a slotted. channelled heel fitting the offset shoulder of the looper bar and a set screw passing through the slot of the looper heel and threaded into the offset shoulder of the looper rod as set forth.

CHARLES A, DEARBORN. 

